[SOLVED] Asus z390, failing to pass the POST, booting in safe mode.

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Oct 29, 2015
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Here are my relevant PC specs

i9 9900k
gtx 2080TI
16gb (2x8) ddr4 2400mhz (XML 1 turned on in BIOS, if I turn it off it makes no difference to the boot issues)
ASUS ROG Strix Z390-E Gaming LGA 1151 (300 Series) Intel Z390 SATA 6Gb/s ATX Intel Motherboard

Before I begin, let me put a few things aside here. This is NOT a bad stick of ram, I have tested 3 brands of DDR4 ram. They all do the same thing. When I use 3 sticks of ram, filling up slot 1,2,3, my PC will boot up normally. If I use 4 sticks of ram, my PC will not boot at all. No matter what slots I put the ram in. However, when I use 2 sticks of ram(1,3 right now), my PC will boot up but it will first get stuck in some weird boot loop. Let me explain.

When I power on my PC, a orange light comes on the mobo near the RAM. My pc holds there for about 5 seconds, and then powers off. It then restarts and shuts off several times, then it will boot to a screen that says my "system failed to post" and is "booting up in safe mode." "Hit f1 to configure."

So I will hit f1, and it will bring me into the BIOS screen. Then I hit escape, save without quit, and then my PC boots normally. I have ran benchmarks, my PC runs just like it should once it finally does get out of the boot cycle. It reads all my memory at the right speeds, right amounts (16gb, currently), it reads my CPU and GPU, the benchmarks are amazing with this system, and I am able to get over 100 FPS on a 1440p monitor with Witcher 3 and around 120 fps with metro exodus. So it clearly is working correctly. . . I assume? I'm not sure what's going on here and I'm at a loss.

Again, it's not bad stick of ram, and I'm positive it's not a bad slot because I have been able to use one stick of ram in each slot to test to see if they work, and they all do work. If I use one stick it will do the same thing it's doing now though, where it boots over and over and then goes into the bios. So it's not ram, not the slots, is there a configuration setting that is messed up, or is this MOBO messed up? If anyone has any tests they want me to run that I maybe haven't thought about, let me know. This is a very expensive build and even though it's working right now, this boot thing is worrying.

Any ideas?
 
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Solution
So, my question would be why are you trying to use 3 sticks of RAM? You couldn't achieve triple channel operation on that board and there are very few memory kits sold in sets of three, although there are SOME, but it won't offer any benefit other than additional memory capacity for your platform and probably doesn't offer any benefit at that unless you are either not gaming with this machine or you have very small sticks.

Slots 1 and 3 are not the correct slots for two DIMM operation.

Check to see that it isn't something like this:



Or this...
So, my question would be why are you trying to use 3 sticks of RAM? You couldn't achieve triple channel operation on that board and there are very few memory kits sold in sets of three, although there are SOME, but it won't offer any benefit other than additional memory capacity for your platform and probably doesn't offer any benefit at that unless you are either not gaming with this machine or you have very small sticks.

Slots 1 and 3 are not the correct slots for two DIMM operation.

Check to see that it isn't something like this:



Or this:


That "weird boot loop" is usually the memory training process. Put two sticks in slots A2 and B2, and make sure they are two sticks that came TOGETHER, in ONE kit, not "mixed" memory that did not come together in one kit.

UB6JJIp.png



Then do a hard reset of the BIOS as follows, and see what happens. You will NEED to go into the BIOS and set the option to use the XMP or DOCP memory profile no matter whether you do the hard reset or not, once you are able to GET into the BIOS.



BIOS Hard Reset procedure

Power off the unit, switch the PSU off and unplug the PSU cord from either the wall or the power supply.

Remove the motherboard CMOS battery for five minutes. In some cases it may be necessary to remove the graphics card to access the CMOS battery.

During that five minutes, press the power button on the case for 30 seconds. After the five minutes is up, reinstall the CMOS battery making sure to insert it with the correct side up just as it came out.

If you had to remove the graphics card you can now reinstall it, but remember to reconnect your power cables if there were any attached to it as well as your display cable.

Now, plug the power supply cable back in, switch the PSU back on and power up the system. It should display the POST screen and the options to enter CMOS/BIOS setup. Enter the bios setup program and reconfigure the boot settings for either the Windows boot manager or for legacy systems, the drive your OS is installed on if necessary.

Save settings and exit. If the system will POST and boot then you can move forward from there including going back into the bios and configuring any other custom settings you may need to configure such as Memory XMP profile settings, custom fan profile settings or other specific settings you may have previously had configured that were wiped out by resetting the CMOS.

In some cases it may be necessary when you go into the BIOS after a reset, to load the Optimal default or Default values and then save settings, to actually get the hardware tables to reset in the boot manager.

It is probably also worth mentioning that for anything that might require an attempt to DO a hard reset in the first place, it is a GOOD IDEA to try a different type of display as many systems will not work properly for some reason with displayport configurations. It is worth trying HDMI if you are having no display or lack of visual ability to enter the BIOS, or no signal messages.
 
Solution

Abominable

Reputable
Oct 29, 2015
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Thank you for your suggestions! I did them, and still no luck. XMP is on, and they are not mixed ram, they are the correct speeds for my CPU, and they are correctly installed dual channel (and recognized in system information as such).

I have the memory in correctly, they are working as dual channel. When I said I put 3 sticks in there, I was just doing that as a test to see if my PC would boot with 3 in there, and it did, with no issues. With 3 sticks it worked, but I obviously didn't keep 3 sticks in there after I ran that test. It also works with one stick, but if I put 2 sticks in, it gets in the boot loop. I can't for the life of me see why 3 sticks would boot fine and 2 wouldn't. It's bizarre.
 
What is the exact model of the memory kit that is comprised of the two sticks? What is the model of the OTHER memory that is not part of that kit?

Have you even TRIED doing a hard reset of the memory with ONLY the two matching sticks, from the same kit (Same part number is NOT the same as being from the same kit, so if these are sticks that did not SPECIFICALLY COME TOGETHER IN A KIT and are only similar specs or even same part number but purchased separately, we are probably wasting our time), installed in the A2 and B2 slots.

Right now I would highly suggest that you remove the CPU cooler, remove the CPU and check the motherboard for bent pins because it certainly sounds as though this fits the typical symptoms of that. I'd also make sure that the CPU cooler is not overly tight, that you used the correct standoffs for the cooler and that nothing is tightened unevenly from side to side or corner to corner. A CPU cooler that is tighter in one spot than the rest can ACT as though there are bent pins because it will tend to "cock" the CPU in the socket and either short pins against something or break the connections to some of the pins, all of which acts much the same as if you HAD bent pins.

Bent pins or mis-installed CPU coolers OFTEN affect memory in weird and funky ways.
 

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